| 1. |
- Aria, S., et al.
(författare)
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GLINT Gravitational-wave laser INterferometry triangle
- 2017
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Ingår i: Experimental Astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 44:2, s. 181-208
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Tidskriftsartikel (refereegranskat)abstract
- When the universe was roughly one billion years old, supermassive black holes (10(3)-10(6) solar masses) already existed. The occurrence of supermassive black holes on such short time scales are poorly understood in terms of their physical or evolutionary processes. Our current understanding is limited by the lack of observational data due the limits of electromagnetic radiation. Gravitational waves as predicted by the theory of general relativity have provided us with the means to probe deeper into the history of the universe. During the ESA Alpach Summer School of 2015, a group of science and engineering students devised GLINT (Gravitational-wave Laser INterferometry Triangle), a space mission concept capable of measuring gravitational waves emitted by black holes that have formed at the early periods after the big bang. Morespecifically at redshifts of 15
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| 2. |
- Bhat, Harshitha K., et al.
(författare)
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Influence of Jets on [O iii] Extensions in Green Pea/Bean Galaxies
- 2024
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Ingår i: Astrophysical Journal. - 1538-4357 .- 0004-637X. ; 960:2
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Tidskriftsartikel (refereegranskat)abstract
- We present a study investigating the influence of jets on galaxies exhibiting strong [O iii]λ5007 emission, known as Green Peas and Green Beans. Our sample comprised 12 nearby sources (z ∼ 0.04-0.1, six with jets and six without jets) with high [O iii] luminosity (L ∼ 1040 erg s−1), selected from a radio-selected galaxy sample observed with the Sloan Digital Sky Survey and Radio Sky at Twenty-centimeters survey. We perform Large Binocular Telescope-Multi-Object Double Spectrograph long-slit spectroscopy at two position angles for each galaxy: one aligned with the jet direction and another perpendicular to it. By tracing the [O iii] emission along these slits, we aimed to assess the extension of the narrow line region and examine the impact of jets. Surprisingly, our analysis revealed no preferred direction for the extension of the [O iii] emission, indicating that jets have a limited influence on the extended emission line regions (EELRs). This also suggests the possibility of missed detection of conical-shaped EELRs aligned with the jets, attributable to our slit orientations. Furthermore, we compared the extension of [O ii] emission, which traces star-forming regions, with that of [O iii]. We observed a significant difference, with [O ii] exhibiting a considerably greater extension along the galactic plane. This suggests a stronger association of [O ii] emission with stellar processes.
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| 3. |
- Misquitta, P., et al.
(författare)
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SDSS-FIRST-selected interacting galaxies: Optical long-slit spectroscopy study using MODS at the LBT
- 2023
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 671
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Tidskriftsartikel (refereegranskat)abstract
- Context. In the hierarchical model of evolution of the Universe, galaxy mergers play an important role, especially at high redshifts. Interactions among galaxies appear to be associated with incidences of radio-loudness in quasars and it is of interest to study the galaxies that are in the process of interacting with each other, where there is at least one nucleus that is active in the radio regime. Aims. In order to understand the various processes taking place within colliding galaxies, it is important to study the radio and optical properties of these sources, as well as any possible correlations that might exist. Methods. To this end, we present optical long-slit spectroscopy data for ten pairs of interacting galaxies selected from SDSS-FIRST at redshifts of ~0.05, observed using the multi-object double spectrographs at the Large Binocular Telescope. Results. We used line fluxes extracted from the spectra of the nuclear regions of galaxies to plot optical diagnostic diagrams and estimate the masses of the central supermassive black holes, as well as their Eddington ratios. Additionally, we used previously published Effelsberg radio telescope data at 4.85 GHz and FIRST survey data at 1.4 GHz to estimate radio spectral slopes and the radio-loudness parameters for all of the radio-detected sources. We also used WISE data to plot a mid-infrared colour-colour diagram. Conclusions. We see that while the sample of galaxies covers all of the classes on the optical diagnostic diagrams, the sources that are radio-detected fall in the composite or transition region of the diagram. Additionally, we notice a trend of the highest radio-loudness parameter in a pair of interacting galaxies being associated with the galaxy that hosts the more massive central supermassive black hole. We do not see any obvious trends with respect to the radio spectral slope, radio-loudness parameter, and Eddington ratio. With respect to the mid-infrared data of the galaxies detected by WISE, we see that most of them have some type of contribution from star formation, however, two of them seem to have a significant contribution from an AGN as well.
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| 4. |
- Pallister, Sam, et al.
(författare)
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A blueprint for a simultaneous test of quantum mechanics and general relativity in a space-based quantum optics experiment
- 2017
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Ingår i: EPJ Quantum Technology. - : Springer Science and Business Media LLC. - 2196-0763. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we propose an experiment designed to observe a general-relativistic effect on single photon interference. The experiment consists of a folded Mach-Zehnder interferometer, with the arms distributed between a single Earth orbiter and a ground station. By compensating for other degrees of freedom and the motion of the orbiter, this setup aims to detect the influence of general relativistic time dilation on a spatially superposed single photon. The proposal details a payload to measure the required effect, along with an extensive feasibility analysis given current technological capabilities.
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| 5. |
- Yttergren, Madeleine, 1990, et al.
(författare)
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Gas and stellar dynamics in Stephan's Quintet Mapping the kinematics in a closely interacting compact galaxy group
- 2021
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 656
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Tidskriftsartikel (refereegranskat)abstract
- In nearby compact galaxy groups we can study the complex processes of galaxy interactions at high resolution and obtain a window into a time in the history of the Universe when the galaxies were closely spaced and the intergalactic medium was awash with gas. Stephan's Quintet is a nearby compact galaxy group and a perfect laboratory for studying the process of galaxy evolution through galaxy harassment and interaction. By analysing the kinematics of Stephan's Quintet we aim to provide an increased understanding of the group, the history of the interactions, their cause and effect, and the details regarding the physical processes occurring as galaxies interact. Ionised gas and stellar kinematics have been studied using data from the Large Binocular Telescope, while the molecular gas kinematics have been obtained from CO observations using the IRAM 30m telescope. Large areas of the group have been mapped and analysed. We obtain a total ionised gas mass in the regions chosen for closer analysis of 20.1 +/- 0.2.10(10) M-circle dot and a total H-2 gas mass of 21 +/- 2.10(9) M-circle dot in the observed area (spectra integrated over the velocity range covering Stephan's Quintet), while the star-forming clouds show an impressive complexity, with gas congregations at multiple velocities at many locations throughout the group. We map the large-scale nuclear wind in NGC7319 and its decoupled gas and stellar disk. With our high resolution data we can, for the first time, reveal the Seyfert 1 nature of NGC7319 and fit the narrow-line region and broad-line region of the H alpha line. While the (CO)-C-12 (1 - 0) map shows significant emission in the area in or near NGC7319, the bridge, and the star-forming ridge, the (CO)-C-12 (2 - 1) emission shows a prevalence to the star-forming ridge, an area south of the NGC7318 pair, and shows an extension towards NGC7317 - connecting NGC7317 to the centre of the group, indicating a previous interaction. NGC7317 may also be a prime candidate for studies of the process of galaxy harassment. Furthermore, we connect the kinematical structures in Stephan's Quintet to the history of the group and the ongoing interaction with NGC7318B. Through our extensive observations of Stephan's Quintet we trace and present the kinematics and evolution of the complex processes and structures occurring in this nearby interactive group.
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